cucumber vine vs melon vine

cucumber vine and melon vine both are nouns.

Word	Noun	Adjective	Verb	Adverb
cucumber vine	Yes	No	No	No
melon vine	Yes	No	No	No

As nouns, melon vine is a hypernym of cucumber vine; that is, melon vine is a word with a broader meaning than cucumber vine:

cucumber vine: a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit
melon vine: any of various fruit of cucurbitaceous vines including: muskmelons, watermelons, cantaloupes, cucumbers

Other hypernyms of cucumber vine include melon.

cucumber vine (noun)	melon vine (noun)
a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit	any of various fruit of cucurbitaceous vines including: muskmelons, watermelons, cantaloupes, cucumbers